Solar control coated glass

ABSTRACT

A solar-control glass that has acceptable visible light transmission, absorbs near infrared wavelength light (NIR) and reflects midrange infrared light (low emissivity mid IR) along with a preselected color within the visible light spectrum for reflected light is provided. Also provided is a method of producing the improved, coated, solar-controlled glass. The improved glass has a solar energy (NIR) absorbing layer comprising tin oxide having a dopant such as antimony and a low emissivity control layer (low emissivity) capable of reflecting midrange infrared light and comprising tin oxide having fluorine and/or phosphorus dopant. A separate iridescence color suppressing layer as described in the prior art is generally not needed to achieve a neutral (colorless) appearance for the coated glass, however an iridescence suppressing layer or other layers may be combined with the two layer assemblage provided by the present invention. If desired, multiple solar control and/or multiple low emissivity layers can be utilized. The NIR layer and the low emissivity layer can be separate portions of a single tin oxide film since both layers are composed of doped tin oxide. A method of producing the coated solar control glass is also provided.

REFERENCE TO RELATED APPLICATION

[0001] The present application is a continuation-in-part of U.S. patentapplication Ser. No. 09/249,761 filed Feb. 16, 1999 which isincorporated herein by reference.

BACKGROUND OF INVENTION

[0002] This invention relates to coated glass used in residential,architectural and vehicle windows and miscellaneous applications whereboth solar control and low emissivity properties are desired. Thecoatings for solar control and low emissivity contain tin oxide havingvarious dopants. The invention avoids the need for an anti-iridescenceunderlayer. The glass articles may be of any shape but are typicallyflat or curved. The glass composition can very widely but is typicallysoda lime glass produced by the float process. It may be annealed, heatstrengthened or tempered.

DESCRIPTION OF PRIOR ART

[0003] Solar-control is a term describing the property of regulating the-amount of solar heat energy which is allowed to pass through a glassarticle into an enclosed space such as a building or an automobileinterior. Low emissivity is a term describing the property of anarticle's surface wherein the absorption and emission of mid-rangeinfrared radiation is suppressed, making the surface a mid-rangeinfrared reflector and thereby reducing heat flux through the article byattenuating the radiative component of heat transfer to and from the lowemissivity surface (sometimes referred to as Low E). By suppressingsolar heat gain, building and automobile interiors are kept cooler;allowing a reduction in air conditioning requirements and costs.Efficient low emissivity coatings improve comfort during both summer andwinter by increasing the thermal insulating performance of a window.

[0004] Important to commercially acceptable coated glass articles whichpossess both solar-control and low emissivity properties are, of course,economic processes for producing the articles and durability andmaintenance of associated properties such as light transmission,visibility, color, clarity and reflection.

[0005] As explained below, various technologies have been employed tomeet the requirement for solar-control and low emissivity glass,however, no one system has successfully met all of the performancerequirements in an economic manner.

[0006] Many coatings and coating systems cause iridescent colors todevelop in the coated article. This may be caused by the chemicalcomposition of the coating , the thickness of an individual layer orlayers, or an interaction of the substrate and coatings to incidentlight. Such iridescence can, in some cases, be minimized or eliminatedby placing an anti-iridescence layer between the glass substrate and thefirst coating. The use of an interference layer between the glass and asubsequent functional layer or layers to suppress iridescence or colorreflection was first demonstrated by Roy G. Gordon, and was the subjectof U.S. Pat. No. 4,187,336, issued Feb. 5, 1980. The Gordon technologyhas been the state of the art for coated solar control glass asevidenced by recently issued U.S. Pat. No. 5,780,149 (McCurdy el al,Jul. 14, 1998) which applied two layers to obtain solar control on topof a Gordon type interference layer. The interference layer frequentlycontains silicon dioxide. Surprisingly, the present invention representsa dramatic breakthrough and eliminates the need for a Gordon typeunderlayer to control reflected color.

[0007] U.S. Pat. No. 3,149,989 discloses compositions of coatings usefulin producing radiation reflecting (solar-control) glass. At least twocoatings are used with the first coating, adhered to the glasssubstrate, being comprised of tin oxide doped with a relatively highlevel of antimony. The second coating is also comprised of tin oxide andis doped with a relatively low level of antimony. The two films may besuperimposed, one on another, or may be applied to opposite sides of theglass substrate. In either case, these solar-control coatings do notcontribute significant low emissivity properties to the glass article.

[0008] U.S. Pat. No. 4,287,009 teaches a heat absorbing glass designedto convert incident sun rays into heat energy that is transferred to aworking fluid for heat transfer. Accordingly, the coated glass absorbsat least 85% of the solar wavelength range rays and has a relatively lowemissivity characteristic of less than 0.2. The coatings are positionedon the outside of the glass (i.e. the side facing the sun) and the fluidfor heat transfer contacts the inside surface of the glass. The coatingscomprise a first coating of metal oxides deposited on the smooth glasslayer which oxides are selected from tin, antimony, indium, and iron anda second coating of metal oxides deposited on the first coating selectedfrom the same group of metals. The films as designed will have very lowvisible transmissions and no teaching on the control of reflected coloris given.

[0009] U.S. Pat. No. 4,601,917 teaches liquid coating compositions forproducing high-quality, high-performance, fluorine-doped tin oxidecoatings by chemical vapor deposition. One of the uses of such coatingsis in the production of energy-efficient windows, also known in thetrade as low-E or low-E windows. Methods of producing the coated glassare also described. This patent does not teach how to produce coatedglass articles which possess both solar-control and low emissivityproperties.

[0010] U.S. Pat. No. 4,504,109, assigned to Kabushiki Kaisha ToyotaChou, describes glass coated with infrared shielding multilayerscomprising a visible light transparent substrate and an overlyingcomponent lamination consisting of “at least one infrared shield layerand at least one interferential reflection layer alternatively lying oneach other . . . ” Indium oxide doped with Sn is used in the examples asthe infrared shield layer and TiO₂ was used as the interferential shieldlayer. In order to reduce iridescence the infrared shield layer and theinterferential reflection layer thickness must have a value of onequarter lambda (lambda/4) with a permissible deviation of from 75% to130% of lambda/4. Although other formulations are disclosed for theinfrared shield layer and the interferential reflection layer such asSnO₂ with or without dopants, (see column 6 lines 12 to 27), however,the specific combination of doped SnO₂ layers of the present inventionthat accomplishes solar control, low emissivity and anti-iridescencewithout requiring a lambda/4 thickness limitation is neither disclosednor exemplified to suppress iridescence or color reflection.

[0011] U.S. Pat. No. 4,583,815, also assigned to Kabushiki Kaisha ToyotaChou describes a heat wave shield laminate consisting of two indium tinoxide overlayers containing different amounts of tin. Antireflectionlayers, above or below the indium tin oxide layers are also described.Other formulations are disclosed for the infrared shield layer and theinterferential reflection layer such as SnO₂ with a dopant that becomesa positive ion with a valence of +5 such as Sb, P, As, Nb, Ta, W, or Moor an element such as F which readily becomes a negative ion with avalence of −1, (see column 22 lines 17 to 23). However, the specificcombination of doped SnO₂ layers of the present invention thataccomplishes solar shielding, low emissivity and anti-iridescence isneither disclosed nor exemplified. There is no claim to tin oxide layersnor any teaching in the specification to describe the composition ofsuch layers, e.g. the ratio of dopant to tin oxide. It should also benoted that the teaching leads to the use of the same dopant in bothlayers (indium tin oxide) whereas in the instant patent application, onelayer must contain a different dopant than the other layer.

[0012] U.S. Pat. No. 4,828,880, assigned to Pilkington PLC, describesbarrier layers which act to inhibit migration of alkali metal ions froma glass surface and/or act as color suppressing underlayers foroverlying infrared reflecting or electrically conducting layers. Some ofthese color suppressing layers are used in solar-control or lowemissivity glass construction.

[0013] U.S. Pat. No. 4,900,634 assigned to Glaverbel discloses apyrolytic coating of tin oxide containing a mixture of fluorine andantimony dopants coated on glass and imparting low emissivity and aspecific haze reduction factor of at most 1.5.

[0014] U.S. Pat. No. 5,168,003, assigned to Ford Motor Company,describes a glazing article bearing a substantially transparent coatingcomprising an optically functional layer (which may be low emissivity orsolar control) and a thinner anti-iridescence layer which is a multiplegradient step zone layer. Antimony doped tin oxide is mentioned as apossible alternative or optional component of the exemplified lowemissivity layer.

[0015] U.S. Pat. No. 5,780,149, assigned to Libbey-Owens-Ford describessolar control coated glass wherein at least three coating layers arepresent, first and second transparent coatings and an iridescencesuppressing layer lying between the glass substrate and the transparentupper layers. The invention relies upon the transparent layers having adifference in refractive indices in the near infrared region greaterthan the difference of indices in the visible region. This differencecauses solar heat to be reflected in the near IR region as opposed tobeing absorbed. Doped metal oxides which have low emissivity properties,such as fluorine doped tin oxide, are used as the first transparentlayer. Metal oxides such as undoped tin oxide are used as the secondlayer. No NIR absorbing combinations are described.

[0016] EP 0-546-302-B1 issued Jul. 16, 1997 and is assigned to AsahiGlass Co. This patent describes coating systems for solar-control, heattreated (tempered or bent) glass comprising a protection layer based ona metal nitride. The protection layer or layers are used to overcoat thesolar-control layer (to prevent it from oxidizing during thermaltreatment). As a solar control layer, many examples are providedincluding tin oxide doped with antimony or fluorine. However, thespecific combination of doped SnO₂ layers of the present invention thataccomplishes solar control, low emissivity and anti-iridescence withoutfollowing Gordon's teachings is neither disclosed nor exemplified.

[0017] EP 0-735-009-A1 is a patent application that was published inFebruary 1996 and is assigned to Central Glass Co. This patentapplication describes a heat-reflecting glass pane having a multilayercoating comprising a glass plate and two layers. The first layer is ahigh refractive index metal oxide based on Cr, Mn, Fe, Co, Ni or Cu, thesecond layer is a lower refractive index film based on a metal oxidesuch as tin oxide. Doped layers and low emissivity or NIR absorbingcombinations are not disclosed.

[0018] WO 98/11031 This patent application was published in March 1998and assigned to Pilkington PLC. It describes a high performancesolar-control glass comprising a glass substrate with coatingscomprising a heat-absorbing layer and a low emissivity layer of a metaloxide. The heat-absorbing layer may be a metal oxide layer. This layermay be doped tungsten, cobalt, chromium, iron molybdenum, niobium orvanadium oxide or mixtures thereof. The low emissivity layer may bedoped tin oxide. In a preferred aspect of the invention, aniridescence-suppressing layer or layers is incorporated under thecoating comprising a heat-absorbing layer and a low emissivity layer.This application does not disclose or suggest the specific combinationof doped SnO₂ layers of the present invention that accomplishes solarcontrol, low emissivity and anti-iridescence without requiring a“Gordon” type underlayer to suppress iridescence or color reflection.

[0019] Canadian Patent 2,193,158 discloses an antimony doped tin oxidelayer on glass with a tin to antimony molar ratio o 1:0.2 to 1:0.5 thatreduces the light transmission of the glass.

[0020]Dopant Effects in Sprayed Tin Oxide Films, by E. Shanthi, A.Banerjee and K. L. Chopra, Thin Solid Films, Vol 88, 1981 pages 93 to100 discusses the effects of antimony, fluorine, and antimony-fluorinedopants on the electrical properties of tin oxide films. The articledoes not disclose any optical properties of the antimony-fluorine filmsnor the effect on transmitted or reflected color.

[0021] UK Patent Application GB 2,302,101 A assigned to Glaverbeldescribes a glass article coated with an antimony/tin oxide film of atleast 400 nm containing an Sb/Sn molar ratio from 0.05 to 0.5, with avisible transmittance of less than 35%. The films are applied by aqueousspray CVD and are intended for privacy glass applications. Haze reducingundercoats are taught as well as thick layers with low Sb/Sn ratioswhich have low emissivity properties as well as high solar absorbency.It also teaches that it is possible to provide one or more additionalcoating layers to achieve certain desirable optical properties. None ofthese properties other than haze are mentioned. The application teachesnothing about thinner layers, the use of more than one dopant, or thecontrol of film color.

[0022] UK Patent Application GB 2,302,102 A also assigned to Glaverbeldescribes a glass substrate coated with a Sn/Sb oxide layer containingtin and antimony in a molar ratio of from 0.01 to 0.5, said layer havingbeen deposited by CVD, whereby the coated substrate has a solarfactor(solar heat gain coefficient) of less than 0.7. The coatings areintended for window applications and have luminous transmittancesbetween 40 and 65% and thicknesses ranging from 100 to 500 nm. Hazereducing undercoats are claimed and low emissivity can be imparted tothe coatings by a judicious choice of the Sb/Sn ratio. Like the previousapplication, the teaching of providing one or more additional coatinglayers to achieve certain desirable optical properties is mentioned.Also low emissivity layers of fluorine doped tin oxide can be depositedover the Sb/Sn layers or fluorine components can be added to the Sb/Snreactants to give low emissivity films which contain F, Sb and Sn. Thelast two methods were not favored because of the added time and cost ofadding a third layer and the fact that the emissivity of the Sb/F filmswas raised and not lowered. No mention of color control or colorneutrality is found.

[0023] GB 2,200139, assigned to Glaverbel teaches a method of depositinga coating by the spray application of solutions containing tinprecursors, fluorine containing compounds and at least one other dopantselected from the group antimony, arsenic, vanadium, cobalt, zinc,cadmium, tungsten, tellurium or manganese.

[0024] Previously, glass manufacturers have managed heat transportthrough windows by the use of absorbing and/or reflecting coatings,glass tints, and post-applied films. Most of these coatings and filmsare designed to control only one portion of the solar heat spectrum,either the NIR, i.e. near infra red component of the electromagneticspectrum having a wavelength in the range of 750-2500 nm or the mid IRcomponent of the electromagnetic spectrum having a wavelength on therange of 2.5-25 microns. A product has been designed to control theentire heat spectrum, however Sputtered metal/dielectric film stackswhile effective, have limited durability and must be protected andsealed within the center section of a multipane insulated glass unit(IGU). What is needed is a total solar control film or combination offilms that can be easily applied by pyrolytic deposition during theglass making operation which yields an article which has an acceptablevisible transmission, reflects or absorbs the NIR, reflects the mid-IR,and is neutral or close to neutral in color.

[0025] The above references either alone or in combination do not teachor suggest the specific combination of doped SnO₂ layers of the presentinvention that accomplishes solar control, low emissivity andanti-iridescence without requiring a “Gordon” type underlayer.

SUMMARY OF THE INVENTION

[0026] The present invention provides an improved solar-control glassthat has acceptable visible light transmission, absorbs near infraredwavelength light (NIR) and reflects midrange infrared light (lowemissivity or Low E) along with a preselected color within the visiblespectrum for reflected light that can be controlled to a specific coloror be made essentially colorless (“neutral” as defined hereinafter).Also provided is a method of producing the improved, coated,solar-control glass. The improved glass coating is a tin oxide coatingwith various dopants and haze modifiers in specific layers of thecoating. One layer is a solar energy (NIR) absorbing layer comprisingtin oxide having a dopant such as antimony. Another layer in the tinoxide coating is a low emissivity control layer capable of reflectingmidrange infrared light and comprising tin oxide having fluorine and/orphosphorus dopant. A separate iridescence color suppressing layer asdescribed in the prior art such as a “Gordon” layer is generally notneeded to achieve a neutral (colorless) appearance for light reflectedoff the coated glass, however an iridescence suppressing layer or otherlayers may be combined with the multilayer tin oxide coating provided bythe present invention. If desired, multiple solar control and/ormultiple low emissivity layers can be utilized. The NIR layer and thelow emissivity layer are separate portions of a single tin oxide filmsince both layers are composed of doped tin oxide. A method of producingthe coated solar control glass is also provided. In addition, thepresent invention controls or changes the color of transmitted lightthrough the addition of color additives to the NIR layer. Surprisinglythe dopant fluorine that produces a noncolored tin oxide film functionsas a color additive when added as an additional dopant to the NIR layerand modifies the color of transmitted light through the NIR film. Alsoprovided are haze reducing dopants in specific layers of the tin oxidecoating.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027]FIGS. 1 through 4 and 8 through 15 depict a cross-section ofcoated glass having different numbers of layers or films in differentstacking sequences for the tin oxide layer on a glass substrate.

[0028]FIGS. 5 and 6 graphically depict the solar control achieved withantimony doped films at various concentrations of dopant and variousfilm thicknesses on window panes, i.e. a single pane of glass, or oninsulated glass units (IGU) which are a composite of at least two glasspanes.

[0029]FIG. 7 depicts the color spectrum in terms of CommissionInternationale de L'Exclairage (C.I.E.) x and y coordinates and thespecific color achievable with various film thickness and dopantconcentrations. The English translation for C.I.E. is InternationalCommission on Illumination

[0030]FIG. 15 shows haze reduction values for tin oxide coatings of thepresent invention with and without haze reducing additives in the NIRlayer, 28.

[0031]FIGS. 16, 17, 18 and 19 graphically depict data developed in theexamples.

OBJECTS OF THE INVENTION

[0032] An object of the invention is to prepare a transparent articlewith controlled reflected color (even neutral color as defined herein,)that will absorb solar near infrared (NIR) wavelength radiation andreflect mid-range infrared heat (low emissivity) comprising glass havinga tin oxide coating composed of two thin film layers containing dopedSnO₂ with haze reducing additives or dopants in at least one of thelayers. Another object is the application of the layers by atmosphericpressure chemical vapor deposition (CVD) techniques, or by otherprocesses such as solution spray or vaporized/sublimed liquids/solidscan be utilized. The preferred method of application for this inventionis atmospheric pressure CVD using vaporized liquid precursors. Anotherobject is to provide multiple solar control and/or low emissivity layersalong with other layers in combination with the solar control or lowemissivity layer. Another object is to provide a solar control film orcombination of films that can be easily applied by pyrolytic depositionduring the glass making operation which yields an article which has anacceptable visible transmission, reflects or absorbs the NIR, reflectsthe mid-IR (low-E), and is neutral or close to neutral in color, theproduction of which is an object of the present invention. Anotherobject of the invention is to control the color of transmitted lightindependently from the color of reflected light by the addition of coloradditives in the NIR layer.

DETAILED DESCRIPTION OF INVENTION AND PREFERRED EMBODIMENTS

[0033] Solar control and low emissivity coated glass is produced bydepositing on a heated transparent substrate at least two layers, a lowemissivity layer comprising a SnO₂ film containing fluorine and/orphosphorus dopant and a NIR absorbing layer comprising a SnO₂ filmcontaining as a dopant antimony, tungsten, vanadium, iron, chromium,molybdenum, niobium, cobalt, nickel or mixtures thereof. Thiscombination has been found to effectively control the solar andradiative heat portions of the electromagnetic spectrum such that awindow coated with these films will have greatly enhanced properties.

[0034] Solar control properties are typically expressed in terms ofsolar heat gain coefficient (SHGC) and U-value. SHGC is a measure of thetotal solar heat gain through a window system relative to the incidentsolar radiation , while the U-value (U) is the total heat transfercoefficient for the window. The SHGC of the coated glass is primarilydependent on the thickness and the antimony content of the NIR absorbingfilm (see FIGS. 5 and 6) while the U-value depends primarily on thefilm's emissivity and the window construction. SHGC measured at centerof glass can range from about 0.40 to 0.80 while U values measured atcenter of glass can vary from about 0.7-1.2 for a single pane coatedwith the preferred embodiment films. In an insulated glass unit (IGU)the SHGC's decrease to ˜0.30 with U-values as low as ˜0.28.

[0035] Both the reflected and transmitted color of the coated glass ofthe present invention can be controlled. In addition the amount ofvisible light transmitted through the coated glass can be controlledbetween about 25-80% by controlling the thickness of the NIR and lowemmisivity films and the concentration of dopant in the NIR film.Transmitted color, i.e. the color of light transmitted through thecoated glass can be controlled separately from the reflected color bythe addition of a color-effective quantity of a color additive to theNIR layer of the coating. The reflected color can vary from almostneutral to red, yellow, blue or green and can be controlled by varyingthe film thickness and dopant content of the layers. Surprisingly, colorneutrality as defined herein can be achieved for reflected color withoutthe need of an anti-iridescent layer. Although the refractive indices ofthe NIR and low emmisivity films are different, the reflected color doesnot depend on classical interference phenomena originally discovered byGordon (U.S. Pat. No. 4,1887,336). Observed reflected color isunexpectedly controlled by the combination of absorption and reflectionachieved by the NIR layer (absorption) and the reflection achieved bythe low-emmisivity layer or layers. The absorption of the NIR layer canbe controlled by varying the thickness of its SnO₂ layer and theconcentration of the dopant in the NIR layer, usually antimony. Thereflectance of the low emissivity layer can be controlled by varying thethickness of its SnO₂ layer and the concentration of the dopant in thelow emissivity layer, usually fluorine. The low emissivity layercomposed of SnO₂ containing a fluorine or phosphorous dopant issometimes abbreviated herein as TOF or TOP while the NIR layer of SnO₂when it contains an antimony dopant is sometimes abbreviated herein asTOSb.

[0036] The preferred embodiment of this invention utilizes a tin oxidecoating that has a fluorine doped tin oxide (TOF) layer as the lowemmisivity layer with an antimony doped tin oxide (TOSb) layer as theNIR layer and with a haze reducing additive in at least one of thelayers preferable in the layer deposited directly onto the glass. TOFfilms and their deposition processes onto glass are known in the art andreferred to as low emissivity films. The NIR absorbing film is also aSnO₂ film but contains a different dopant than the low emissivity layer.The dopant in the NIR layer is preferably antimony although the dopantcan be an element selected from the group consisting of antimony,tungsten vanadium, iron, chromium, molybdenum, niobium, cobalt, nickel,and mixtures thereof. A mixture of one or more dopants can be used inthe NIR layer, however the low emissivity layer must contain a lowemissivity dopant that imparts significant conductivity to the layersuch as fluorine or phosphorous, although other dopants may be used incombination with the low emissivity dopant. Since the low emissivity andthe NIR layers of the present invention both utilize SnO₂ as the metaloxide matrix containing a dopant, the NIR and the low emissivity layersare preferably part of a single film having a dopant gradient or layershaving different dopants. A single film utilizing a dopant gradient isdepicted in FIG. 3 as film 16. In film 16 there is a dopant gradientwith the NIR dopant having a higher concentration than the otherdopant(s) at one surface of the film, either surface 18 or 22, and thelow emissivity dopant having a higher concentration than the otherdopants at the other surface of the film. This results in a change orgradient in the concentrations of the NIR and low emissivity dopantsbetween surface 18 and surface 22. At some intermediate point 20 betweensurface 18 and surface 22 the concentration of the NIR dopant changesfrom being the highest concentration dopant on one side of point 22 tono longer being the highest concentration dopant on the other side ofpoint 22. FIG. 8 shows the low e film, 10, above the NIR film 12, TheNIR film 12 in FIG. 8 has a concentration gradient for the NIR dopant inthe tin oxide film with a lower concentration of the dopant closer tothe low e film 10. The coated glass of FIG. 9 is similar to thestructure shown in FIG. 8 with the exception that the concentrationgradient of the NIR dopant, usually antimony, is higher near the low efilm 10 and lower nearer the substrate. Film 12 is different then film16 shown in FIG. 3 in that film 12 is a NIR film while film 16 has bothNIR and low e properties and contains both a low e dopant and a NIRdopant with a concentration gradient for the low e dopant and aconcentration gradient for the NIR dopant. FIGS. 10, 11, 12 and 13 showthe NIR layer as two distinct films, 28 and 30. Film 28 is shown asbeing thicker than film 30 and the total thickness of the NIR layer isthe sum of the thicknesses of films 28 and 30 and should be within therange of thicknesses stated above for the NIR layer and preferably from80 to 300 nm. In FIGS. 10 and 11, films 28 and 30 are adjacent eachother, while in FIGS. 12 and 13, films 28 and 30 are on opposite sidesof low e film 10. The concentration of dopant in film 28 is preferablydifferent than the concentration of dopant in film 30.

[0037]FIG. 14 shows a bilayer tin oxide film deposited directly on aglass substrate 14 with the lower layer 32 being one section, 34 havinga haze reducing additive and and other portion, 36 without an hazereducing additive, while the top layer, 10 is a low emissivity layersuch as fluorine doped tin oxide.

[0038]FIG. 15 shows haze reduction values for tin oxide coatings of thepresent invention with and without haze reducing additives in the NIRlayer, 32. Shown are four glass substrates each having an antimony dopedtin oxide NIR layer, 32, about 2400 angstroms thick beneath a fluorinedoped low e layer, 10 each about 3000 angstroms thick. In the coatedglass on the left, haze was 1.13% verses 0.72% when TFA was added to theNIR layer shown on the second from the left. Continuing to the right inFIG. 15, the haze of the bilayer coating 32 and 10, is 0.84 when waterwas withheld during the deposition of the first 550 (approximately)angstroms of the NIR layer, verses a haze of 0.70 shown in the far rightbilayer coated glass in which the TFA but no water was present among theprecursors that deposited the first 550 angstroms of NIR layer 32

[0039] The preferred embodiment of this invention uses an antimony dopedfilm as the NIR film. Such a film can be deposited by a number oftechniques including spray pyrolysis, PVD and CVD methods. Spraypyrolysis is known and disclosed in patents such as Canadian patent2,193,158. CVD methods for depositing SnO₂ films with or without dopantsand the chemical precursors for forming SnO₂ films containing dopantsare well known and disclosed in U.S. Pat. Nos. 4,601,917, and 4,265,974.Preferred is CVD deposition of the SnO₂ layers containing dopantsaccording to known methods directly on a float glass manufacturing lineoutside of or within the float glass chamber utilizing conventionalon-line deposition techniques and chemical precursors as taught by U.S.Pat. No. 4,853,257 (Henery). However the SnO₂ films containing dopantscan be applied as layers on glass utilizing other processes such assolution spray or vaporized/sublinied liquids/solids at atmosphericpressure. When the application is by solution spray the same SnO₂precursors and dopants are dissolved in a suitable non-reactive solventand applied by known spray techniques to the hot glass ribbon atatmospheric pressure. Suitable solvents for the solution sprayapplication as taught in Canadian Patent Application 2,193,158 includealcohols such as ethanol and isopropanol, ketones such as acetone and2-butanone, and esters such as ethyl acetate and butyl acetate. Thepreferred method of application for this invention is atmosphericpressure CVD using vaporized liquid precursors. The process is veryamenable to existing commercial on-line deposition systems. Theprecursors of the preferred embodiments are economical to apply, willenable long coating times, will reduce the frequency of systemclean-out, and should be able to be used with little or no modificationto existing glass float line coating equipment,

[0040] The coatings function by a combination of reflection andabsorption. The low emissivity film reflects mid-IR heat in the 2.5-25micron region of the spectrum while the NIR absorbing film absorbs heatprimarily in the 750-2500 nm region. While not to be bound thereby, thetheory upon which we account for this effect is that in the NIR region,the plasma wavelength (PL—the wavelength where the low emissivity filmchanges from a transmitter to a reflector of light energy) for the lowemissivity film falls in the NIR region. In the area around the PL, theNIR absorption is the highest for the low emissivity film and whencombined with a NIR absorbing film, increased absorbency takes place.The NIR absorbing films of our preferred embodiments are also dopedsemi-conductors and hence have reflective properties in the mid IR. Thisreflection coupled with the low emissivity film reflection gives anoverall higher heat reflectance in the mid IR.

[0041] Preferably the SnO₂ is pyrolyticly deposited on the glass using atin precursor, especially an organotin precursor compound such asmonobutyltin trichloride (MBTC), dimethyltin dichloride, dibutyltindiacetate, methyl tin trichloride or any of the known precursors for CVDdeposition of SnO₂ such as those disclosed in U.S. Pat. No. 4,601,917incorporated herein by reference. Often such organotin compounds used asprecursors for pyrolytic deposition of SnO₂ contain stabilizers such asethanol. Preferably the concentration of stabilizers is less than 1% inorder to reduce fire risks when contacting hot glass with such chemicalsin the presence of oxygen. Precursors for the dopant in the NIR layer(antimony, tungsten, vanadium, iron, chromium, molybdenum, niobium,cobalt and nickel) are preferably halides such as antimony trichloride,however alkoxides, esters, acetylacetonates and carbonyls can be used aswell. Other suitable precursors for the dopant and SnO₂ are well knownto those skilled in the art. Suitable precursors and quantities for thefluorine dopant in the low emissivity SnO₂ layer are disclosed in U.S.Pat. No. 4,601,917 and include trifluoroacetic acid,ethyltrifluoroacetate, ammonium fluoride, and hydrofluoric acid.Concentration of low emissivity dopant is usually less then 30% withpreferred concentrations of low emissivity dopant from 1% to 15% byweight of dopant precursor based upon the combined weight of dopantprecursor and tin precursor. This generally correlates to a dopantconcentration in the low e film of from 1% to 5% percent based upon theweight of tin oxide in the low e film.

[0042] In our preferred embodiments, the properties depend on thethickness of the low emissivity and absorbing layers as well as theantimony content of the absorbing (NIR) film. The low emissivity filmthickness can range from 200-450 nm with to 320 nm being most preferred.The preferred NIR absorbing films can be deposited in a similar fashionas the low emissivity films using such methods as disclosed in U.S. Pat.No. 4,601,917. The organotin precursors for the SnO₂ can be vaporized inair or other suitable carrier gases containing a source of O₂ and inprecursor concentrations from 0.25-4.0 mol % (0.5-3.0 mol % morepreferred). SnO₂ precursor concentrations are expressed herein as apercentage based upon the moles of precursor and the moles of carriergas. Preferred concentrations of NIR dopant precursor are from about 1%to about 20% (2.5% to 7.5% more preferred and 3.0% to 6.0% mostpreferred) and are calculated using the weight of dopant precursor andthe weight of SnO₂ precursor. Particularly preferred is an antimonydopant using antimony trichloride as the precursor at about 2% to about8% by weight with about 4.0% by weight particularly preferred. Thiscorrelates to a similar antimony mass percent in the tin oxide NIR film.

[0043] The coated glass of the present invention is depicted in thefigures. FIG. 1 shows the films in cross section. The film thicknessescan range from 200 to 450 nm for the low emissivity film (item 10) andfor the NIR film (item 12) from 80 to 300 nm. The preferred thickness is250 to 350 nm for the low emmisivity film and 200 to 280 nm for the NIRfilm. Most preferred is 280 to 320 nm for the low e film and 220-260 nmfor NIR film. Using films of the preferred embodiments, solar controlcoated glass can be produced with a Neutral-blue Color which is definedherein as coated glass having reflected light predominately withinC.I.E. chromaticity coordinates values of x between 0.285 and 0.310 andy between 0.295 and 0.325. The definition of Neutral-blue is shown inFIG. 7 by the area within the box labeled Neutral-blue Color. As shownin FIG. 7, with examples 15, 20 and 22, controlled or preselectedreflected color close to neutral color but slightly to the yellow sideof neutral can be produced (x values of up to 0.325 and y values of upto 0.33), but such essentially neutral to slightly yellow shades ofreflected color are not appealing to consumers. FIG. 2 shows the twofilms or layers in the opposite sequence than that shown in FIG. 1. InFIG. 2, the low emissivity film is closer to the glass 14 than the NIRfilm 12. FIG. 3 shows the NIR and the low emissivity layers integratedinto a single SnO₂ film 16 having a dopant gradient within film 16. Film16 has a preponderance of one dopant (e.g. the low emissivity dopant,fluorine) at the upper surface, 18, away from the glass 14 and apreponderance of the other dopant (e.g. the NIR dopant such as antinony)at the film surface 22 nearer the glass. The concentration of dopantchanges from surface 18 to surface 22, so that one dopant changes fromgreater than 50% of the dopants at surface 18 to approximately 0% atsurface 22. At an intermediate point 20, below upper surface 18, thepredominant dopant at that point in the film changes from thepredominant dopant at surface 18 to the predominant dopant at surface22. Either the NIR dopant or the low emissivity dopant (fluorine) can bethe predominant dopant at surface 18 with the other dopant thepredominant dopant, at surface 22. FIG. 4 depicts a coated glass havingadditional layers 24 and 26 in addition to a low emissivity layer 10 andNIR layer 12. The additional layers 24 and 26 can be additional lowemissivity and/or NIR layers or other conventional layers used to coatglass such as a tinting layer. For example 12 can be a NIR layer (e.g.antimony doped tin), 10 a low emissivity layer (fluorine doped tin) and24 another NIR layer. 26 can be another low emissivity layer or someother conventional layer. The concentration of dopant when more than onelow emissivity layer is utilized may be the same or different and thethickness of each low emissivity layers may also be the same ordifferent. Likewise, when more than one NIR layer is utilized, theconcentration of dopant and the selection of dopant (antimony, tungsten,vanadium, iron, chromium, molybdenum, niobium, cobalt and nickel) can bethe same or different and the thickness of each NIR layer can be thesame or different. Generally the dopant for the NIR layer has beendiscussed herein mostly in terms of antimony, it must be understood thatthe dopant in the NIR layer can be selected from the group consisting ofantimony, tungsten, vanadium, iron, chromium, molybdenum, niobium,cobalt, nickel and mixtures thereof. Likewise, in the gradient layerembodiment of the invention as depicted in FIG. 3, the predominantdopant at the NIR surface either surface 18 or 22 can be selected fromthe group consisting of antimony, tungsten, vanadium, iron, chromium,molybdenum, niobium, cobalt, nickel and mixtures thereof, it only beingessential that the low e dopant, e.g. fluorine, be the predominantdopant at the opposite surface. Combined with a gradient layer can beone or more NIR or low emissivity layers such as layers 10 and 12 inFIGS. 1 to 3 and/or other conventional layers.

[0044] Water is preferably used to accelerate the deposition of SnO₂film onto glass as taught by U.S. Pat. No. 4,590,096 (Lindner) and usedin concentrations from ˜0.75 to 12.0 mol % H₂O based upon the gascomposition.

[0045] Another embodiment of this invention is the reduction of filmhaze. Haze is due to the scattering of incident light when it strikes asurface. It can be caused by surface roughness due to large crystallitesize, a wide range of crystallite sizes and/or particulates imbedded inthe film surface. It can also be caused by voids (holes) in the film dueto the volatilization of an intermediate by-product such as NaCl. Thefilms deposited by this invention have haze that is predominantly causedby surface roughness. Haze is reduced by the judicious inclusion orexclusion of certain additives in the coating process either at theglass-film interface or at the bi-layer film interface. By controllingthe rugosity within the film layers in this manner, the rugosity andhence the haze of the top layer in the bilayer tin oxide coating isreduced. This is an improvement over the prior art which obtains hazereduction by adding an auxiliary layer on top of the functional layer.The sole purpose of the prior art auxiliary layer is to level the roughsurface of the functional layer by filling in the areas betweencrystallite peaks and valleys.

[0046] One of these rugosity reducing additives is fluorine in either aninorganic form like HF or an organic form like trifluoroacetic acid(TFA) or ethyl trifluoroacetate for example. Other fluorine sourcessuitable for haze reduction are difluoroacetic acid, monofluoroaceticacid, antimony tri and pentafuoride, and ethyl trifluoroacetoacetate.When fluorine is present in all or part of the TOSb undercoat, thecrystallite size is significantly decreased and the overall film haze isreduced. SEM micrographs show that the crystallite size of the topcoathas been affected by the reduced crystallite size of the undercoat.Other additives that have been found to be effective in reducing hazeare acids such as acetic, formic, propionic, methanesulfonic, butyricand its isomers, nitric and nitrous acid. Haze also can be reduced bythe exclusion of certain additives such as water. When water is notpresent during the deposition of the first few hundred angstroms of theundercoat, the overall crystallite size is reduced. Haze can also bereduced by combining one or more of the above aspects. If TFA isincluded in the deposition process when water is being excluded, theoverall film haze is reduced. For example, when water is removed fromthe deposition of the first 50-60 nm of the TOSb layer, overall filmmorphology is reduced and haze values of ˜0.8% are achieved. If TFA isadded and water excluded from the deposition of the first 50-60 nm ofthe TOSb layer, similar morphology effects and haze values are recorded.

[0047] Fluorine, when added as a dopant into a tin oxide film, decreasesemissivity and increases film conductivity. However, it is notfunctioning as such a traditional dopant in this invention when it isadded to the antimony doped layer of the tin oxide coating. It functionsin the antimony doped layer as a modifier of the crystallite size of theantimony doped tin oxide as manifested in the reduction of overall filmhaze (measured on a hazemeter and confirmed by SEM micrographs). Theincrease in sheet resistance with the associated increase in emissivity,shown in the results in Table 3, confirms the function of the addedfluorine to the antimony doped tin oxide layer (TOSb). When fluorine ispresent in the TOSb layer, the resultant emissivity of the combinedlayer is increased, not decreased as would be expected if it werefunctioning as a dopant. While not willing to be bound to theexplanation, it is believed that fluorine may preferentially bind to theantimony sites thereby effectively removing both as dopants in the filmand hence the overall film emissivity would increase.

[0048] Another embodiment of the invention provides the ability tochange the transmitted color of the coated glass. Transmitted colorrefers to the color perceived by a viewer on the opposite side of thecoated glass from the source of light being viewed, while reflectedcolor is the color perceived by a viewer on the same side as the sourceof light being viewed. Transmitted light can be effected by addingadditional dopants to the NIR film. As previously explained, the NIRlayer contains a dopant selected from the group consisting of antimony,tungsten, vanadium, iron, chromium, molybdenum, niobium, cobalt andnickel. The color of transmitted light through the NIR layer can bechanged by adding an additional dopant different then the first dopantin the NIR layer and selected from the group consisting of tungsten,vanadium, iron, chromium, molybdenum, niobium, cobalt, nickel or acombination of more then one additional dopant to the NIR layer. Thehaze additive, fluorine, can also effect transmitted color. As shown inexamples 40-43, the addition of a fluorine precursor, such astrifluoroacetic acid (TFA) to a NIR precursor solution such asSbCl₃/MBTC, produces a film whose transmitted color is gray versus ablue transmitted color for an antimony doped tin oxide layer withoutfluorine dopant. The additive has little or no effect on reflected lightand accordingly, a coated glass can be produced having a reflected lightthat is different then its transmitted light.

[0049] Dopants in the NIR layer such as vanadium, nickel, chromium andnon-traditional color additives such as trifluoroacetic acid (TFA) canbe added to the TO:Sb precursors in 1-5 wt % (based on the total wt ofprecursor and additive) to effect transmitted color changes in the finalfilm construction while not significantly affecting overall reflectedcolor neutrality.

[0050] The preferred embodiments of our invention will be exemplified bythe following examples. One skilled in the art will realize that minorvariations outside the embodiments stated herein do not depart from thespirit and scope of this invention.

[0051] The most preferred embodiments, at this time, to obtain a coatedglass with low e and NIR properties with neutral reflected color from atin oxide coating composed of only two layers, irrespective of haze, aredescribed in Examples 1 to 30. One layer is about a 3000 Å thick TO:Ffilm (fluorine doped tin oxide) in combination with about a 2400 Å TO:Sb(antimony doped tin oxide) film on glass. The film thickness for theTO:F layer can range from ˜2800-3200 Å and still achieve the surprisingresult of a neutral reflected color. The fluorine concentration canrange from ˜1-5 atomic %. The TO:Sb film thickness can range from˜2200-2600 Å with an antimony concentration from ˜3-8% and still achievethe surprising result of a neutral reflected color for the coated glass.Within the preferred thickness and dopant concentration ranges of thepresent invention, a solar control coated glass can be produced having aNIR layer and a low e layer and having a Neutral-blue Color forreflected light, i.e. coated glass having reflected light predominatelywithin C.I.E. chromaticity coordinates values of x between 0.285 and0.310 and y between 0.295 and 0.325 as shown in FIG. 7 by a box labeledNeutral-blue Color.

[0052] All SHGC and U values in the tables have been determined usingthe single band approach of the NFRC Window 4.1 program. Use of the moreaccurate multiband approach (spectral data file required) will improvethe SHGC's by approximately 14%.

[0053] The C.I.E. tristimulus values for the reflected and transmittedcolors of the coated articles can be calculated according to ASTMStandard E 308, with Illuminant C used as the standard illuminant. Fromthis ASTM Standard E 308, the color of an object can be specified withone of several different scales. The scale used for the coated articlesin this invention is the C.I.E. 1931 chromaticity coordinates x and y.One can easily translate to the C.I.E. 1976 L*, a*, b* opponent-colorscale by using the following equations:

x=X/(X+Y+Z)

y=(X+Y+Z)

L*=116(Y/Y _(n))^(1/3)−16

a*=500[(X/X _(n))^(1/3)−(Y/Y _(n))^(1/3)]

b*=200[(Y/Y _(n))^(1/3)−(Z/Z _(n))^(1/3)]

[0054] where X, Y, and Z are the C.I.E. tristimulus values of the coatedarticle, and X_(n), Y_(n), and Z_(n), are 98.074, 100.000, and 118.232,respectively, for Standard Illuminant C. from the L*, a*, b* values, thecolor saturation index, c*, can be calculated by the equationc*=[(a*)²+(b*)²]^(1/2). A color saturation index of 12 or less isconsidered neutral.

[0055] The definition of Neutral-blue Color for reflected light, i.e.coated glass having reflected light predominately within C.I.E.chromaticity coordinates values of x between 0.285 and 0.310 and ybetween 0.295 and 0.325 as shown in FIG. 7 by a box labeled Neutral-blueColor correlates with C.I.E. 1976 L*, a*, b* of 37.85, −1.25, −5.9 and39.62, −2.25, 1.5.

[0056] A sample conversion follows:

[0057] Example 40 (Table 3)

[0058] 5.5 % SbCl₃

[0059] 300/240 (F/Sb/Glass)

[0060] X=9.797

[0061] Y=9.404

[0062] Z=12.438

[0063] x=0.310

[0064] y=0.297

[0065] L*=36.751

[0066] a*=4.624

[0067] b*=−3.466

[0068] c*=5.778

[0069] Solar control properties of glass windows has been evaluated andrated by the United States of America, Environmental Protection Agencyusing an Energy Star rating system. An Energy Star rating for theCentral Region of the United States requires a U-factor rating of 0.40or lower and a SHGC rating of 0.55 or below. An Energy Star rating forthe Southern Region of the United States requires a U-factor rating of0.75 or lower and a SHGC rating of 0.40 or below. Coated glass havingthe NIR and Low e coatings ofthe present invention and when incorporatedinto windows of conventional design achieve the Energy Star ratings forthe Central and/or Southern Region. For example a Vertical slider designwindow 3 feet wide by 4 feet high and having a frame absorption value of0.5 as rated by the National Fenestration Rating Council (NFRC) andassembled with coated solar control glass of the present inventionhaving a NIR film and a low e film within the preferred ranges for aNeutral-Blue Color achieves a SHGC of less than 0.40 and a U value ofless than 0.64 for a monolith glass construction with a frame U-value of0.7 or less and achieves a SHGC of less than 0.38 and a U value of lessthan 0.48 for an Insulated Glass Unit (IGU) construction made up with2.5 mm clear lite, 0.5 inch air gap and NIR and Low e coatings on the #2surface of the outer lite and a frame U-value of 1.0 or less.

[0070] The examples will substantiate that with a minimum of two dopedSnO₂ layers, an excellent solar control coated glass can be producedhaving a preselected reflected color. Tables 1, 2 and 3 present the datawhile FIGS. 5 and 6 show graphically how the solar properties of thecoated glass vary with dopant concentrations and film thicknessprimarily of the NIR film. FIG. 7 plots the x and y C.I.E. chromaticitycoordinates of a representative selection of coated glass of Examples 1to 30. As seen in FIG. 7, specific combinations of film thicknesses forboth the NIR and low emissivity films and specific dopant(s)concentrations can be utilized to produce a coated, solar control glasswith any desired color for light reflected off the coated surface of theglass, such as red, green, yellow, blue and shades thereof orNeutral-blue Color. It is particularly surprising that a Neutral-blueColor can be achieved with a NIR and a low emissivity layers but withoutan anti-iridescence layer such as taught by Gordon.

[0071] While the inventive features ofthe present invention can beachieved with only two layers, a NIR layer and a low emissivity layer,multilayer embodiments are within the scope and content of theinvention. The multilayers can be additional NIR and/or low emissivitylayers or other functional or decorative layers. Multilayer embodimentsinclude TOSb/TOF/TOSb/Glass, or TO/TOF/TOSb/Glass, or TO/TOSb/TOF/Glasswith TO being just a tin oxide film. When multiple NIR or low emissivitylayers are used, the dopant concentrations or dopant selection in eachNIR or low emissivity film need not be the same. For example when twoNIR layers are used in combination with at least one low emissivitylayer, one NIR layer can have a low level of antimony dopant (e.g. 2.5%)to give some reflectance in the mid IR range and one layer can have ahigher level (≧5%) to give NIR absorbency. The terms layer and film aregenerally used herein interchangeably except in the discussion ofgradient film depicted in FIG. 3 in which a portion ofthe film isreferred to as a layer having a dopant concentration different than thedopant concentration in another layer of the film. In the method ofmaking the coated glass of the present invention as demonstrated in theexamples, the glass is contacted sequentially with carrier gascontaining precursors. Accordingly, the glass may have a coating on itwhen it is contacted a second time with a carrier gas containingprecursors. Therefore, the term “contacting glass” refers to eitherdirect contact or contact with one or more coatings previously depositedon the glass. The best ways to practice the haze reduction aspects ofthis invention are described in Examples 40-43 and 48-61. The resultsare summarized in Tables 3, 4, and 5.

EXAMPLES 1 TO 30

[0072] A 2.2 mm thick glass substrate (soda lime silica), two inchessquare, was heated on a hot block to 605 to 625° C. The substrate waspositioned 25 mm under the center section of a vertical concentric tubecoating nozzle. A carrier gas of dry air flowing at a rate of 15 litersper minute (l/min) was heated to 160° C. and passed through a hot wallvertical vaporizer. A liquid coating solution containing ˜95 wt %monobutyltin trichloride and ˜5 wt % antimony trichloride was fed to thevaporizer via a syringe pump at a volume flow designed to give a 0.5 mol% organotin concentration in the gas composition. A quantity of waterwas also fed into the vaporizer at a flow designed to give a 1.5 mol %water vapor in the gas mixture. The gas mixture was allowed to impingeon the glass substrate at a face velocity of 0.9 m/sec for ˜6.1 secondsresulting in the deposition of a film of antimony doped tin oxide ˜240nm thick. Immediately following, a second gas mixture was usedconsisting of a precursor composition of 95 wt % monobutyltintrichloride and 5 wt % trifluoroacetic acid, along with water in thesame concentrations and carrier gas as used before to deposit theantimony doped SnO₂ layer. This second gas mixture was allowed toimpinge on the coated substrate for ˜6.7 seconds. A film of ˜280 nm offluorine doped tin oxide was deposited. The bilayer film was very lightblue in transmission and reflection. The optical properties weremeasured on a UV/VIS/NIR spectrophotometer and the sheet resistance wasmeasured on a standard four point probe. The solar heat gaincoefficient, U value and visible transmission for the center of theglass were calculated using the Window 4.1 program developed by LawrenceBerkeley National Laboratory, Windows and Daylight Group, BuildingTechnologies Program, Energy and Environmental Division. The C.I.E.chromaticity x and y color coordinates were calculated using ASTME308-96 from the visible reflectance data between 380-770 nm and thetristimulus values for Illuminant C. The analysis results for this filmappears in Table 1, number 19. The procedure of this example wasrepeated 29 additional times with concentrations of chemical precursorsand deposition times varied in order to produce coated glass sampleshaving different thicknesses for the NIR and low emissivity layers anddifferent dopant concentrations. The results are presented in Table 1.

EXAMPLES 31 TO 38

[0073] The procedure of Example 1 was repeated, except that the vaporfeed order was reversed. The fluorine doped tin oxide film was depositedfirst for ˜8 seconds followed by the antimony doped tin oxide film for˜6 seconds. The resulting film was ˜540 nm thick and composed of a lowemissivity layer (TOF) of about 300 nm and a NIR layer (TOSb) of about240 nm and had a similar appearance and reflected light color(Neutral-blue Color) as the film in example 19. The analysis resultsappear in Table 2, number 31. The procedure of this example was repeated7 additional times with concentrations of chemical precursors anddeposition times varied in order to produce coated glass samples havingdifferent thicknesses for the NIR and low emissivity layers anddifferent dopant concentrations. The results are presented in Table 2.

EXAMPLE 39

[0074] The procedure of Example 1 was repeated but utilizing threeprecursor feed mixtures. The composition of the third mixture was 90 wt% monobutyltin trichloride, 5 wt % trifluoroacetic acid, and 5 wt %antimony trichloride. A gradient film was deposited by first depositingonly the antimony doped tin oxide precursor of Example 1 for 70% of thetime needed to deposit 240 nm. Then the mixed antimony/fluorine dopedprecursor was started. Both precursor mixtures would continue for 20% ofthe total deposition time at which point the antimony precursor mixturewas turned off. The antimony/fluorine mixed precursor was continued forthe remaining 10% of the total deposition time for the 240 nm antimonyfilm. At this point, the fluorine doped tin oxide film precursor feedwas turned on. Both feeds were continued for 20% of the total timeneeded to deposit 300 nm of fluorine doped tin oxide. The mixedantimony/fluorine precursor feed was turned off and the fluorine dopedtin precursor was continued for the remaining deposition time for thefluorine doped film. The resultant gradient coating layer is light bluein transmitted and reflected color (x=0.292, y=0.316) a SHGC=0.50, a Uvalue=0.6, and a visible transmission about 45%. As shown in FIG. 3,surface 22 of gradient film 16 would have essentially 100% antimonydopant while surface 18 would have essentially 100% fluorine dopant witha gradient in dopant concentration between surfaces 18 and 22 and allwithin a film matrix of SnO₂.

EXAMPLES 40 TO 43

[0075] The procedure of Example 1 was used in Examples 40 to 43. Thecoating composition for the NIR layer in Examples 41 and 43 was composedof a fluorine, antimony, and tin precursor made by adding SbCl3 and TFAto MB TC. This precursor contained 0-5% by weight TFA, 5.2-5.5% byweight SbCl3, and the remainder MBTC, and was co-fed with water into thesecond vaporizer. The carrier gas used for the second vaporizer was dryair at a rate of 15 l/min. The fluorine/antimony/tin precursor was addedat a rate of 0.5 mole percent of total carrier gas flow, the water wasadded at a rate of 1.5 mole percent total carrier gas flow, and thevaporizer temperature was maintained at 160C. A soda-lime-silica glasssubstrate two inches square and 2.2 mm thick was preheated on a heaterblock to 605 to 625C. The heater block and substrate were then moved toa position directly beneath the vertical coater nozzle, with thesubstrate being 25 mm beneath the coater nozzle. F/Sb/Sn/H2O vapors fromthe second vaporizer were then directed onto the glass substrate,depositing a fluorine containing antimony doped tin oxide undercoatlayer in examples 41 and 43. The velocity of the carrier gas was 0.9 m/sand the thickness of the doped tin oxide film was ˜240 nm. Reactionbyproducts and unreacted precursor vapors were exhausted from thesubstrate at a rate of 18 l/min. After the antimony and fluorine dopedtin oxide undercoat was deposited, the coater nozzle valve was switchedfrom the second vaporizer feed to the first vaporizer feed. MBTC/TFA/H2Ovapors from the first vaporizer feed were then directed onto thesubstrate, depositing a layer of fluorine doped tin oxide directly ontop of the antimony/fluorine tin oxide undercoat. The velocity of thecarrier gas was 0.9 m/s and the thickness of the fluorine doped tinoxide film was ˜300 nm. The bilayer films in examples 41 and 43(containing both F and Sb in the NIR undercoat) were light grey intransmitted color and neutral in reflected color. Examples 40 and 42essentially reproduce examples 41 and 43 respectively but withoutfluorine in the NIR undercoat layer. The properties were measured andthe results appear in Table 3. The results show how fluorine, as anadditive in the NIR layer, acts as a color modifier as well as a hazereducer for both reflected and transmitted color. The transmittedcolors, T_(vis), x and y, of the films made with the TFA and Sb dopantsin the NIR layer, Examples 41 and 43, are more neutral in reflectedcolor and greyer in transmitted color then those which only contained Sbas a dopant in the antimony doped tin oxide NIR layer in examples 40 and42. Furthermore, the antimony doped NIR layer with a color effectingquantity of fluorine dopant has greater transmission of visible light(increase in T_(vis) from 54.5 to 58.5 in example 41 versus example 42with the some level of antimony dopant). TABLE 3 Summary of Propertiesof Bilayer Films TOSb/TOF Ex. # 40 41 42 43 Composit. F/Sb/G F/Sb-F/GF/Sb/G F/Sb-F/G % SbCl3 5.5 5.2 5.2 5.36 % Additive 0 TFA 5 TFA 0 TFA2.5 TFA Thick. nm 300/240 300/240 300/240 300/240 % Asol 45.5 35.7 41.839.1 % Tsol 45.0 54.2 48.2 50.6 % Rsol, 1 9.5 10.1 10.0 10.3 % Rsol, 28.0 8.9 8.4 8.7 % Tvis 50.9 58.5 54.5 55.6 % Rvis, 1 9.4 10.1 10.4 10.3% Rvis, 2 8.0 9.0 8.5 9.0 % Tuv 40.1 41.1 41.6 39.8 S. R, 11.9 13.7 11.812.5 Emis-cal 0.12 0.13 0.11 0.12 Glass L # 6235 6236 6237 6238 SHGCc0.53 0.60 0.55 0.57 SHGCc IG 0.45 0.52 0.47 0.49 Uc 0.72 0.73 0.72 0.72Uc IG 0.27 0.28 0.27 0.27 Tvis-c 0.51 0.59 0.55 0.56 Tvis-c IG 0.46 0.530.50 0.51 R1 x 0.310 0.296 0.302 0.303 R1 y 0.297 0.313 0.299 0.306 %Rvis 9.4 10.1 10.4 10.3 Tvis x 0.294 0.308 0.297 0.304 Tvis y 0.3080.315 0.310 0.314 % Haze 2.22 ± 0.18 1.60 ± 0.29 2.34 ± 0.19 1.72 ± 0.26

[0076] Examples 44 through 47 demonstrate the deposition of films withthe following composition: TOF/TOSb (low Sb conc.)/TOSb (high Sbconc.)/Glass, TOF/TOSb (high Sb conc.)/TOSb (low Sb conc.)/Glass, TOSb(low Sb)/TOF/TOSb (high Sb conc.)/Glass, and TOSb (high Sb)/TOF/TOSb(low Sb conc.)/Glass.

EXAMPLE 44

[0077] The procedure of Example 1 was repeated except that the glasstemperature was about 610° C. and the concentration of reagents wasabout 0.63 mol % in air flowing at a rate of 20 liters per minute. About400 Å of antimony doped tin oxide was deposited first from a liquidcoating solution composed of about 10 wt % antimony trichloride and ˜90%monobutyltin trichloride. Immediately following, a second layer of about2000 Å of antimony doped tin oxide from a liquid coating solutioncomposed of 3.25% antimony trichloride and 96.75% monobutlytintrichloride was deposited. A third layer composed of about 3000 Å offluorine doped tin oxide was deposited from a solution containing 5 wt %trifluoroacetic acid and 95 wt % monobutyltin trichloride. The resultingfilm appeared to have a light green-blue color for reflected light andlight blue color for transmitted light. The film properties weremeasured as described in Example 1. The visible light transmission was64% and the SHGC was calculated to be 0.56. The x and y coordinates forthe color of reflected light were 0.304 and 0.299, respectively, puttingthe film in the neutral-blue color quadrant of C.I.E. color space asdefined earlier.

EXAMPLE 45

[0078] The procedure of Example 44 was repeated, but this time the TOSblayers were deposited in reverse order (sometimes referred to herein asreverse construction). The resulting film was blue-red in reflectedcolor with color coordinates of (x) 0.330 and (y) 0.293, respectively. Avisible transmission of 59% and a SHGC of 0.54 were obtained. Oneskilled in the art will realize that the TOSb layers can be of differentthicknesses and concentrations than described herein and still be withinthe scope of this invention.

EXAMPLE 46

[0079] The procedure of Example 44 was repeated, but in this example thedeposition sequence of the fluorine doped tin oxide layer and the 3.25%antimony trichloride solution layer were reversed. The resulting filmhad a visible transmission of about 62%, a SHGC of 0.55, and a neutralblue-red reflected color characterized by color coordinates (x) 0.311and (y) 0.311.

EXAMPLE 47

[0080] The procedure of Example 45 was repeated, but in this example thedeposition sequence of the fluorine doped tin oxide layer and the 10.0%antimony trichloride solution layer were reversed. The resulting filmhad a visible transmission of about 57%, a SHGC of 0.53, and a lightgreen reflected color characterized by color coordinates (x) 0.308 and(y) 0.341. One skilled in the-art will realize that the TOSb layers canbe of different thicknesses and concentrations than described herein andstill be within the scope of this invention.

EXAMPLE 48

[0081] The procedure of Example 41 was repeated with the followingchanges. The precursor coating composition for the NIR layer wascomposed of 5% by weight TFA, 4.35% by weight SbCl3, and the remainderMBTC. The carrier gas used for the vaporization was dry air at a rate of20 l/min. The fluorine/antimony/tin precursor was added at a rate of 1.5mol percent of total carrier gas flow, the water was added at a rate of7.5 mol percent total carrier gas flow, and the vaporizer temperaturewas maintained at 160C. A soda-lime-silica glass substrate two inchessquare and 2.2 mm thick was preheated on a heater block to 640° C.Precursor vapors were directed onto the glass substrate at a velocity of˜1.2 m/s and a fluorine and antimony containing tin oxide film of ˜240nm was deposited at a rate of ˜1200 Å/sec. Immediately after thisdeposition, a fluorine doped tin oxide layer of ˜300 nm was deposited atthe same rate from a vapor composition of 1.5 mol percent TFA/MBTC (5%by weight TFA and 95% by weight MBTC), 7.5 mol percent water vapor andthe remainder air. The bilayer film was blue-green in reflected colorand had a haze value of 1.20% as measured on a Gardner Hazemeter.

EXAMPLE 49

[0082] The procedure of Example 48 was repeated but water was omittedfrom the vapor stream for the deposition of the first ˜300-600 Å of theantimony and fluorine containing tin oxide first layer. The resultingfilm had a measured haze of 0.97%, a 20% reduction from the previousExample.

COMPARATIVE EXAMPLE 50

[0083] The procedure of Example 40 was repeated with the followingchanges. The precursor coating composition for the NIR layer wascomposed of 6.75% by weight SbCl3 and the remainder MBTC. The carriergas used for the vaporization was dry air at a rate of 20 l/min. Theantimony/tin precursor was added at a rate of 1.5 mol percent of totalcarrier gas flow, the water was added at a rate of 7.5 mol percent oftotal carrier gas flow, and the vaporizer temperature was maintained at,160C. A soda-lime-silica glass substrate two inches square and 2.2 mmthick was preheated on a heater block to 648° C. Precursor vapors weredirected onto the glass substrate at a velocity of ˜1.2 m/s and anantimony doped tin oxide film of ˜240 nm was deposited at a rate of˜1200 Å/sec. Immediately after this deposition, a fluorine doped tinoxide layer of ˜300 nm was deposited at the same rate from a vaporcomposition of 1.5 mol percent TFA/MBTC (5% by weight TFA and 95% byweight MBTC), 7.5 mol percent water vapor and the remainder air. Thebilayer film was blue-green in reflected color and had a haze value of1.34% as measured on a Gardner Hazemeter.

EXAMPLE 51

[0084] The procedure of Example 50 was repeated but water was omittedfrom the vapor stream for the deposition of the first ˜300-600 Å of theantimony doped tin oxide first layer. The resulting film had a measuredhaze of 0.90%, a 33% reduction from the previous Example.

EXAMPLE 52

[0085] The procedure of Example 51 was repeated but 5% by weight TFA wasadded to the precursor solution for the deposition of the first ˜300-600Å of the antimony doped tin oxide first layer. The resulting film had ameasured haze of 0.83%, a 38% reduction from the haze in Example 50.

EXAMPLE 53

[0086] The procedure of Example 50 was repeated but 5% by weight TFA wasadded to the precursor solution for the deposition ofthe antimony dopedtin oxide first layer. The resulting bilayer film had a measured haze of1.17%.

EXAMPLE 54

[0087] The procedure of Example 40 was repeated with the followingchanges. The precursor coating composition for the NIR layer wascomposed of 6.75% by weight SbCl3 and the remainder MBTC. The carriergas used for the vaporization was dry air at a rate of 20 l/min. Theantimony/tin precursor was added at a rate of 1.5 mol percent of totalcarrier gas flow, the water was added at a rate of 1.5 mol percent totalcarrier gas flow, and the vaporizer temperature was maintained at 160C.A soda-lime-silica glass substrate two inches square and 2.2 mm thickwas preheated on a heater block to 663° C. Precursor vapors weredirected onto the glass substrate at a velocity of ˜1.2 m/s and anantimony doped tin oxide film of ˜240 nm was deposited at a rate of˜1050 Å/sec. Immediately after this deposition, a fluorine doped tinoxide layer of ˜300 nm was deposited at the same rate from a vaporcomposition of 1.5 mol percent TFA/MBTC (5% by weight TFA and 95% byweight MBTC), 1.5 mol percent water vapor and the remainder air. Thebilayer film was blue-green in reflected color and had a haze value of1.13% as measured on a Gardner Hazemeter.

EXAMPLE 55

[0088] The procedure of Example 54 was repeated but water was omittedfrom the vapor stream during the deposition of the first ˜300-600 Å ofthe antimony doped tin oxide first layer. The resulting film had ameasured haze of 0.90%, a 20% reduction from the previous Example.

EXAMPLE 56

[0089] The procedure of Example 55 was repeated but 5% by weight TFA wasadded to the precursor solution during the deposition of the first˜300-600 Å of the antimony doped tin oxide first layer. The resultingfilm had a measured haze of 0.70%, a 23% reduction from the previousExample.

EXAMPLE 57

[0090] The procedure of Example 54 was repeated but 5% by weight TFA wasadded to the precursor solution used for the deposition of the antimonydoped tin oxide first layer. The resulting bilayer film had a measuredhaze of 0.72%, a 36% reduction from the haze measured in Example 54.

[0091] The following examples illustrate the haze obtained when thebilayer film is deposited in reverse order.

EXAMPLE 58

[0092] The procedure of Example 31 was repeated with the followingchanges. The precursor coating composition for the underlayer wascomposed of 5.0% by weight TFA and 95% by weight MBTC. The carrier gasused for the vaporization was dry air at a rate of 20 l/min. Theprecursor solution was added at a rate of 1.5 mol percent of totalcarrier gas flow, the water was added at a rate of 1.5 mol percent oftotal carrier gas flow, and the vaporizer temperature was maintained at160C. A soda-lime-silica glass substrate two inches square and 2.2 mmthick was preheated on a heater block to 663° C. Precursor vapors weredirected onto the glass substrate at a velocity of ˜1.2 m/s and afluorine doped tin oxide film of ˜300 nm was deposited at a rate of˜1050 Å/sec. Immediately after this deposition, an antimony doped tinoxide layer of ˜240 nm was deposited at the same rate from a vaporcomposition of 1.5 mol percent SbCl₃/MBTC (6.75% by weight SbCl₃ and93.25% by weight MBTC), 1.5 mol percent water vapor and the remainderair. The resulting bilayer film was neutral blue in reflected color andhad a haze value of 0.68% as measured on a Gardner Hazemeter.

EXAMPLE 59

[0093] The procedure of Example 58 was repeated, but 5% by weight TFAwas added to the precursor solution used for the deposition of theantimony doped tin oxide first layer. The resulting bilayer film was aneutral blue in reflected color and had a haze value of 0.67%.

EXAMPLE 60

[0094] The procedure of Example 54 was repeated, but 2.9% by weightacetic acid was added to a 5.75% by weight SbCl₃/MBTC precursor solutionused for the deposition of the antimony doped tin oxide first layer. Theresulting bilayer film was a neutral blue in reflected color and had ahaze value of 0.95%.

COMPARATIVE EXAMPLE 61

[0095] The procedure of Example 60 was repeated, but with no acetic acidin the precursor solution. The resulting bilayer film was a neutral bluein reflected color and had a haze value of 1.37%.

[0096] The results of examples 48 to 61 are given in Tables 4 and 5TABLE 4 Effects of TFA &/or H₂O On Haze of Bilayer Films Ex.# 48 49 5051 52 53 54 Composit.* 2 2 1 1 2 2 1 % SbCl3 4.35 4.35 6.75 6.75 6.756.75 6.75 % TFA 5 5 0 0 5 5 0 1^(st) 30-60 nm Y Y N N Y Y N In rest Y YN N N Y N H₂O/Sn 5 5 5 5 5 5 1 1^(st) 30-60 nm Y N Y N N Y Y In rest Y YY Y Y Y Y Rate (Å/s) ˜1200 ˜1200 ˜1200 ˜1200 ˜1200 ˜1200 ˜1050 Temp. °C. 640 640 648 648 648 648 663 % Haze 1.20 0.97 1.34 0.90 0.83 1.17 1.13Ex.# 55 56 57 58 59 Composit.* 1 2 2 3 4 % SbCl3 6.75 6.75 6.75 6.756.75 % TFA 0 5 5 0 5 1^(st) 30-60 nm N Y Y N Y In rest N N Y N Y H₂O/Sn1 1 1 1 1 1^(st) 30-60 nm N N Y Y Y In rest Y Y Y Y Y Rate (Å/s) ˜1050˜1050 ˜1050 ˜1050 ˜1050 Temp. ° C. 663 663 663 663 663 % Haze 0.90 0.700.72 0.68 0.67

[0097] TABLE 5 Effects of Acetic Acid On Haze of Bilayer Films Ex. # 6061 Composit.* 2 2 % SbCl3 5.75 5.75 % HAC 2.9 0 1^(st) 30-60 nm Y N Inrest Y N H₂O/Sn 1 1 1^(st) 30-60 nm Y Y In rest Y Y Rate (Å/s) ˜1050˜1050 Temp. ° C. 663 663 % Haze 1.37 0.95

[0098] Silica can also function as a haze reducing additive in the tinoxide NIR layer adjacent to the glass especially when added to the topportion of the NIR layer prior to the deposition of the low E layer ontop of the NIR layer. The preferred silica precursor istetramethylcyclotetrasiloxane (TMCTS). A 33% haze reduction was obtainedwhen TMCTS was used in the last ˜600 Å of the undercoat. Examples 62 and63 and the results thereof in Table 6 illustrate the effects of silicaas a haze reducing additive in the antimony doped tin oxide layer.

EXAMPLE 62

[0099] The procedure of Example 1 was repeated with the followingchanges. The precursor coating composition for the NIR layer wascomposed of two solutions, a 5.75% by weight SbCl3 with the remainderMBTC fed to both vaporizers and a neat solution oftetramethylcyclotetrasiloxane (TMCTS) fed only to the second vaporizer.The carrier gas used for the vaporization was dry air at a rate of 15l/min. The antimony/tin precursor was added at a rate of 0.5 mol percentof total carrier gas flow, the water was added in the upstream mixingsection of the coater at a rate of 1.5 mol percent in total carrier gasflow, and the vaporizer temperature was maintained at 160° C. When theTMCTS was used, it was fed at a rate of 0.05 mol%. A soda-lime-silicaglass substrate two inches square and 2.2 mm thick was preheated on aheater block to 663° C. NIR layer precursor vapors were directed ontothe glass substrate at a velocity of ˜0.88 m/s and an antimony doped tinoxide film of ˜185 nm was deposited at a rate of ˜55 nm/sec. Immediatelyafter this deposition, an antimony doped tin oxide film containingsilica was deposited from the second vaporizer at the same rate to athickness of ˜61 nm. This was followed by a fluorine doped tin oxidelayer of ˜298 nm which was deposited from the first vaporizer at thesame rate from a vapor composition of 0.5 mol percent TFA/MBTC (5% byweight TFA and 95% by weight MBTC), 1.5 mol percent water vapor and theremainder air. The deposited film was neutral blue in reflected colorand had a haze value of 0.81% as measured on a Gardner Hazemeter.

COMPARATIVE EXAMPLE 63

[0100] The procedure of Example 62 was repeated except that the antimonydoped tin oxide layer was 223 nm thick, no silica containing layer wasdeposited, and the TOF layer was 291 nm. The resulting film had a hazevalue of 1.20% as measured on the Gardner Hazemeter. TABLE 6 Effect ofTMCTS On Haze of Solar Control Films Ex # 62 63 Composition TOF/TOSb-TOF/TOSb/G Si/TOSb/G % SbCl3 5.75 5.75 TOSb nm 185 223 Mol TMCTS/mol Sn0.1 0 TOSb-Si nm 61 0 TOF nm 298 291 Rate (Å/s) ˜550 ˜550 Temp. ° C. 663663 % Haze 0.81 1.20

We claim:
 1. A tin oxide coated, solar control glass having low haze ofless than about 2.0% and having a NIR solar absorbing layer and a lowemissivity layer within said tin oxide coating, comprising a glasssubstrate and a doped tin oxide coating having at least two layers withone layer being a solar absorbing layer comprising SnO₂ containing adopant selected from the group consisting of antimony, tungsten,vanadium, iron, chromium, molybdenum, niobium, cobalt, nickel andmixtures thereof and another layer being a low emissivity layercomprising SnO₂ containing a dopant selected from the group fluorine orphosphorus and a portion of said solar absorbing layer having reducedrugosity that contributes to reduced rugosity and low haze for said tinoxide coating.
 2. The coated glass of claim 1 wherein the thickness ofthe solar absorbing layer is from 200 to 320 nanometers (nm) and thethickness of the low emissivity layer is from 200 to 450 nm and whereinsaid portion of said solar absorbing layer imparting reduced rugositycontains a haze reducing quantity of a haze reducing additive selectedfrom the group consisting of fluorine, and the pyrolytic decompositionproduct of tetramethylcyclotetrasiloxane, HF, difluoroacetic acid,monofluoroacetic acid, antimony trifluoride, antimony pentafuoride,ethyl trifluoroacetoacetate, acetic , formic acid, propionic acid,methanesulfonic acid, butyric acid and its isomers, nitric acid ornitrous acid.
 3. The coated glass of claim 1 wherein the thickness ofthe NIR solar absorbing layer is from 200 to 320 nanometers (nm) and thethickness of the low emissivity layer is from 200 to 450 nm and theportion of said solar absorbing layer having reduced rugosity comprisesthe pyrolytic decomposition product of an anhydrous (dry) mixturecontaining the precursor of tin and the precursor of antimony.
 4. Thecoated glass of claim 1 wherein the thickness of the NIR solar absorbinglayer is from 200 to 320 nanometers (nm) and the thickness of the low,emissivity layer is from 200 to 450 nm and the portion of said solarabsorbing layer imparting reduced rugosity comprises from 300 Angstroms(Å) to 600 Å of the thickness of the solar absorbing layer and islocated either adjacent to the interface between the solar absorbinglayer and the low emissivity layer, or is the portion of the solarabsorbing layer that is closest to the glass substrate.
 5. The coatedglass of claim 2 wherein the thickness of the NIR solar absorbing layeris from 200 to 320 nanometers (nm) and the thickness of the lowemissivity layer is from 200 to 450 nm and portion of said solarabsorbing layer having reduced rugosity comprises from 300 Angstroms (Å)to 600 Å of the thickness of the solar absorbing layer.
 6. The coatedglass of claim 1 wherein said solar absorbing layer is located closer tothe glass substrate than the low emissivity layer.
 7. The coated glassof claim 1 wherein said solar absorbing layer has a thickness from 220to 260 nm, an antimony dopant concentration of from 2.5% to 7% by weightin said solar absorbing layer based upon the weight of SnO₂ in saidsolar absorbing layer, and the low emissivity layer has a thickness offrom 280 to 320 nm, a fluorine dopant concentration of from 1% to 5% byweight in said low emissivity layer based upon the weight of SnO₂ insaid low emissivity layer.
 8. The glass of claim 1 wherein the solarabsorbing layer is coated directly onto the glass and the low emissivitylayer is coated on top of the solar control layer.
 9. The glass of claim1 wherein the solar absorbing layer is SnO₂ having an antimony dopantwithin the range of 3% to 6% by weight based upon the weight of SnO₂ tinoxide in the solar control layer, the low emissivity control layer isSnO₂ having a fluorine dopant within range of 1% to 3% dopant by weightbased upon the weight of SnO₂ in the low emissivity layer and saidportion of said solar absorbing layer imparting reduced rugositycontains fluorine in sufficient quantity to raise the conductivity ofsaid portion of the solar absorbing layer.
 10. A tin oxide coated, solarcontrol glass having low haze and having a NIR solar absorbing layer anda low emissivity layer within said tin oxide coating, comprising a glasssubstrate and a doped tin oxide coating having at least two layers withone layer being a solar absorbing layer comprising an antimony dopedSnO₂ and another layer being a low emissivity layer comprising SnO₂containing a dopant selected from the group fluorine or phosphorus and aportion of said solar absorbing layer being the pyrolytic decompositionproduct of a precursor of tin, a precursor of antimony and a hazereducing quantity of a haze reducing additive selected from the groupconsisting of a precursor of fluorine, tetramethylcyclotetrasiloxane,HF, difluoroacetic acid, monofluoroacetic acid, antimony trifluoride,antimony pentafuoride, ethyl trifluoroacetoacetate, acetic acid, formicacid, propionic acid, methanesulfonic acid, butyric acid and itsisomers, nitric acid and nitrous acid.
 11. The coated, solar controlglass of claim 3 wherein said solar absorbing layer has a thickness from200 to 320 nm, an antimony dopant concentration of from 2.5% to 7% byweight in said solar absorbing layer based upon the weight of SnO₂ insaid solar absorbing layer, and the low emissivity layer has a thicknessof from 200 to 450 nm, a fluorine dopant concentration of from 1% to 5%by weight in said low emissivity layer based upon the weight of SnO₂ insaid low emissivity layer.
 12. The coated glass of claim 1 wherein thesolar absorbing layer is coated directly onto the glass and the lowemissivity layer is coated on top ofthe solar control layer.
 13. Thecoated glass of claim 1 further comprising an additional film coatingthe glass either between the glass substrate and the tin oxide coatingor above the tin oxide coating.
 14. An antimony doped tin oxide filmcontaining a haze reducing quantity of a haze reducing additive selectedfrom the group consisting of fluorine and the pyrolytic decompositionproduct of tetramethylcyclotetrasiloxane, HF, difluoroacetic acid,monofluoroacetic acid, antimony trifluoride, antimony pentafuoride,ethyl trifluoroacetoacetate, acetic, formic acid, propionic acid,methanesulfonic acid, butyric acid and its isomers, nitric acid ornitrous acid.
 15. An antimony doped tin oxide film having low hazecomprising a pyrolytic decomposition product of an anhydrous (dry)mixture containing a precursor of tin and a precursor of antimony and asource of oxygen.
 16. A multilayer antimony doped tin oxide film havinglow haze wherein the first layer comprises a pyrolytic decompositionproduct of an anhydrous (dry) mixture containing a precursor of tin, aprecursor of antimony and a source of oxygen, and the second layer is apyrolytic decomposition product of a mixture containing a precursor oftin, a precursor of antimony, water and a source of oxygen.
 17. Anantimony doped tin oxide film having low haze produced by the pyrolyticdecomposition of a mixture containing a precursor of tin, a precursor ofantimony, a source of oxygen and a haze reducing quantity of a hazereducing additive selected from the group consisting of a precursor offluorine, a precursor of phosphorous, tetramethylcyclotetrasiloxane, HF,difluoroacetic acid, monofluoroacetic acid, antimony trifluoride,antimony pentafuoride, ethyl trifluoroacetoacetate, acetic, formic acid,propionic acid, methanesulfonic acid, butyric acid and its isomers,nitric acid or nitrous acid.
 18. The antimony doped tin oxide film ofclaim 17 wherein the precursor of antimony is selected from the groupconsisting of antimony trichloride, antimony pentachloride, antimonytriacetate, antimony triethoxide, antimony trifluoride, antimonypentafluoride, and antimony acetylacetonate.
 19. The coated glass ofclaim 1 wherein each of the SnO₂ layers is a pyrolytic decomposition ofa tin precursor.
 20. The coated glass of claim 19 wherein the tinprecursor is selected from the group consisting of monobutyltintrichloride, methyltin trichloride, dimethyltin dichloride, dibutyltindiacetate, and tin tetrachloride.
 21. The coated glass of claim 1wherein the solar absorbing layer is composed of at least two solarabsorbing films and the total thickness of the solar absorbing films isform 80 to 320 nm.
 22. The coated glass of claim 21 wherein theconcentration of dopant in one of said solar absorbing films isdifferent than the concentration of dopant in another of the solarabsorbing films.
 23. The coated glass of claim 1 wherein the lowemissivity layer is composed of at least two low emissivity films andthe total thickness of the low emissivity films is form 200 to 450 nm.24. The coated glass of claim 23 wherein the concentration of dopant inone of said low emissivity films is different than the concentration ofdopant in another of the low emissivity films.
 25. The coated glass ofclaim 1 further comprising a transmitted color modifying quantity of adopant in said solar absorbing layer.
 26. The coated glass of claim 25wherein said color modifying dopant is fluorine.
 27. The coated glass ofclaim 1 further comprising fluorine as a non-dopant, rugosity effectingadditive in said solar absorbing layer.
 28. A method of producing thecoated glass of claim 1 comprising sequentially treating glass at aglass temperature above 400° C. with: a first carrier gas containing asource of oxygen, H₂O, a tin precursor and a dopant precursor selectedfrom the group consisting of antimony trichloride, antimonypentachloride, antimony triacetate, antimony triethoxide, antimonytrifluoride, antimony pentafluoride, or antimony acetylacetonate to formby pyrolysis a NIR layer comprising SnO₂ containing an antimony dopant;an anhydrous second carrier comprising oxygen, a tin precursor and adopant precursor selected from the group consisting of antimonytrichloride, antimony pentachloride, antimony triacetate, antimonytriethoxide, antimony trifluoride, antimony pentafluoride, or antimonyacetylacetonate to form by pyrolysis a NIR layer comprising SnO₂containing an antimony dopant to form by pyrolysis a NIR layercomprising SnO₂ containing an antimony dopant and having reducedrugosity that contributes to reduced haze; a third carrier gascomprising gas containing a source of oxygen, H₂O, a tin precursor and adopant precursor selected from the group consisting of trifluoroaceticacid, ethyltrifluoroacetate, difluoroacetic acid, monofluoroacetic acid,ammonium fluoride, ammonium bifluoride, and hydrofluoric acid, to form alow emissivity layer comprising SnO₂ containing a fluorine dopant.
 29. Amethod of producing the coated glass of claim 1 comprising sequentiallytreating glass at a glass temperature above 400° C. with: a firstcarrier gas containing a source of oxygen, H₂O, a tin precursor and adopant precursor selected from the group consisting of antimonytrichloride, antimony pentachloride, antimony triacetate, antimonytriethoxide, antimony trifluoride, antimony pentafluoride, or antimonyacetylacetonate to form by pyrolysis a NIR layer comprising SnO₂containing an antimony dopant; a second carrier comprising oxygen, tinprecursor, a dopant precursor selected from the group consisting ofantimony trichloride, antimony pentachloride, antimony triacetate,antimony triethoxide, antimony trifluoride, antimony pentafluoride, orantimony acetylacetonate, and a haze reducing quantity of a hazereducing additive selected from the group consisting of a precursor offluorine, tetramethylcyclotetrasiloxane, HF, difluoroacetic acid,monofluoroacetic acid, antimony trifluoride, antimony pentafuoride,ethyl trifluoroacetoacetate, acetic formic acid, propionic acid,methanesulfonic acid, butyric acid and its isomers, nitric acid ornitrous acid to form by pyrolysis a NIR layer comprising SnO₂ containingan antimony dopant to form by pyrolysis a NIR layer comprising SnO₂containing an antimony dopant and having reduced rugosity thatcontributes to reduced haze; a third carrier gas comprising gascontaining a source of oxygen, H₂O, a tin precursor and a dopantprecursor selected from the group consisting of trifluoroacetic acid,ethyltrifluoroacetate, difluoroacetic acid, monofluoroacetic acid,ammonium fluoride, ammonium bifluoride, and hydrofluoric acid, to form alow emissivity layer comprising SnO₂ containing a fluorine dopant. 30.The method of claim 28 wherein said glass substrate is contacted withthe second carrier gas before it is contacted with the first carriergas.
 31. The method of claim 28 wherein said glass substrate iscontacted with the second carrier gas before it is contacted with thefirst carrier gas.
 32. The method of claim 29 wherein said glasssubstrate is contacted with the second carrier gas before it iscontacted with the first carrier gas and the haze reducing additive is aselection other than tetramethylcyclotetrasiloxane.
 33. The method ofclaim 29 wherein said glass substrate is contacted with the firstcarrier gas before it is contacted with the second carrier gas and thehaze reducing additive is tetramethylcyclotetrasiloxane.
 34. The methodof claim 32 wherein said second carrier gas is anhydrous.
 35. Theproduct produced by the method of claim
 28. 36. The product produced bythe method of claim 29.